Many visually interesting lighting effects can be obtained by cyclically pulsing light intensity and/or color. For example, many fundamental biological phenomena are related to frequencies in the range of 0.01 Hz and 100 Hz, and their pulsations resonate deeply within human perception. For example, it is well established that when one is exposed to light pulsations within the frequency range of typical brainwaves (approximately 2 Hz to 30 Hz), the brain has a tendency to eventually fall in synchronism with the light pulsations: this phenomenon is known as photic brainwave entrainment. Since different brainwave frequencies are associated to different mind states, it follows that light pulsations can have an influence on mood and state of mind. As another example, pulsations near the typical heartbeat frequency of 1.2 Hz usually strongly attract the attention. As yet another example pulsations at 7.8 Hz, a frequency known as the “Schumann Resonance” which relates to the resonance frequency of the electromagnetic field surrounding the Earth, are perceived as very soothing by most people
Light pulsations are already commonly generated in parts of this frequency range with stroboscope-type luminaires such as seen in discotheques or ambiance lighting systems. However, such systems usually generate crude on/off light pulses, as shown in FIG. 1 (PRIOR ART), which can trigger epileptic episodes in some individuals. Current research indicates that 1 in 20,000 adults over 25 years of age have epileptic photosensitivity to pulsing light, without necessarily being aware of it. While this risk associated to standard stroboscopic light pulsations is minimal, it cannot be ignored in lighting applications for the general public.
Extensive psychophysiological research allows us to specify the arousing, relaxing, awareness sharpening, or pacifying effects of various colors. Such research originates in the early work of pioneers such as Dinshah Ghadiali (1863-1966) with his Spectro-Chrome Color Therapy system, and includes treatment modalities such as Syntonic Optometry as developed by Dr. Spitler from 1927. More recent examples include the research of Dr. John Nash Ott (author of “Health and Light”, 1973), Dr. Fritz Hollowich (author of “The influence of ocular light perception on metabolism in man and animal”, 1969) and Jacob Liberman (Light: Medecine of the Future”, 1984). For example, it is well established that so-called cool colors (in the green-blue spectrum) have a tendency to stimulate the parasympathetic portion of the autonomous nervous system (ANS), leading to reduced pulse rate and relaxation. Conversely, so-called warm colors (in the red-orange-yellow spectrum) have a tendency to stimulate the sympathetic portion of the ANS, leading to increased pulse rate and arousal. Intermediate colors (lime and magenta) have a tendency to bring balance and equilibrium between both portions of the ANS. Due to limitations of existing colored light generation technology, most existing color therapy systems have been making use of the application of single static colors, sometimes presented in sequences of chosen colors.
Combining the effect of color with brainwave photic driving has been shown to have great therapeutic potential. Previous inventions making use of this combination include the Photron and Lumitron by John Downing (1984) and the Color Receptivity Trainer by Jacob Liberman (1991). However these devices can only present a single color combined with a single stroboscopically pulsing frequency, with a changing of either parameter requiring a manual intervention.
There may be therapeutic benefits in presenting more complex light projections involving the simultaneous presentation of more than one color, or sequences of colors in a more rapid succession than that allowed by manual control (e.g. more than once per second). Furthermore, there may be therapeutic benefits to combining colors with brainwave pulsations of the colored light intensity without incurring the discomfort of stroboscopic flashes or the risk of epileptic complications. As will be shown below, such modulated light projections can prove particularly effective to induce relaxing, energizing or balancing effects in humans and animals. Through facilitating the induction of a state of deep relaxation, they can also prove particularly effective in reducing stress levels. It is well-known in medical science that stress is a major contributor in a wide variety of health problems: recent research suggests that anywhere from 60 to 90 percent of illness is stress-related. The above-described modulated light projections may therefore assist in the treatment of pathologies generated by excessive stress of the nervous system.
Prior art in the field of light modulation includes U.S. Pat. No. 5,070,399 (MARTEL) entitled “Light Color and Intensity Modulation System”, issued in 1991, which describes a system comprising a color scaling device receiving a hue control signal and producing a plurality of color component signals being supplied as the output to color light projectors, and one LFO whose output is an intensity modulation signal for varying the intensity of the plurality of color component signals. While such a system is capable of performing basic light modulation as shown in FIG. 2 (PRIOR ART), its capabilities are limited to a single type of visual effect, i.e., the intensity modulation with one frequency.
There remains however a need for improved systems in this field.